History

Polydactyly is the most common congenital digital anomaly of the hand and foot. It may appear in isolation or in association with other birth defects.^[9]

Physical Examination

Temtamy and McKusick^[10]classified polydactyly into preaxial, central, and postaxial types. Preaxial polydactyly refers to the duplication of the first digit. Central polydactyly involves duplication of the second, third, or fourth digit. Postaxial polydactyly involves the fifth digit. The terms radial, central, and ulnar can be used to describe polydactyly in the upper extremity. Similarly, the terms tibial, central, and fibular can be used to describe polydactyly in the lower extremity.

The association of hand and foot polydactyly is uncommon. If hand and foot polydactyly does occur, it may be a case of "crossed polydactyly"—when preaxial involement of the hand and postaxial involvement of the foot occurs or vice versa.

Synpolydactyly is the combination of syndactyly and polydactyly.^{[11, 12]}

Differential Diagnoses

Hosalkar HS, Shah H, Gujar P, Kulkarni AD. Crossed polydactyly. J Postgrad Med. 1999 Jul-Sep. 45(3):90-2. [QxMD MEDLINE Link].
Wattanarat O, Kantaputra PN. Preaxial polydactyly associated with a MSX1 mutation and report of two novel mutations. Am J Med Genet A. 2015 Oct 13. [QxMD MEDLINE Link].
Bouldin CM, Harfe BD. Aberrant FGF signaling, independent of ectopic hedgehog signaling, initiates preaxial polydactyly in Dorking chickens. Dev Biol. 2009 Oct 1. 334 (1):133-41. [QxMD MEDLINE Link].
Muragaki Y, Mundlos S, Upton J, Olsen BR. Altered growth and branching patterns in synpolydactyly caused by mutations in HOXD13. Science. 1996 Apr 26. 272(5261):548-51. [QxMD MEDLINE Link].
Chen X, Yuan L, Xu H, Hu P, Yang Y, Guo Y, et al. Novel GLI3 Mutations in Chinese Patients with Non-syndromic Post-axial Polydactyly. Curr Mol Med. 2019. 19(3):228.
Finley WH, Gustavson KH, Hall TM, Hurst DC, Barganier CM, Wiedmeyer JA. Birth defects surveillance: Jefferson County, Alabama, and Uppsala County, Sweden. South Med J. 1994 Apr. 87(4):440-5. [QxMD MEDLINE Link].
Cohen MS. Thumb duplication. Hand Clin. 1998 Feb. 14(1):17-27. [QxMD MEDLINE Link].
Hung L, Cheng JC, Bundoc R, Leung P. Thumb duplication at the metacarpophalangeal joint. Management and a new classification. Clin Orthop Relat Res. 1996 Feb. 31-41. [QxMD MEDLINE Link].
Klaassen Z, Shoja MM, Tubbs RS, Loukas M. Supernumerary and absent limbs and digits of the lower limb: a review of the literature. Clin Anat. 2011 Jul. 24(5):570-5. [QxMD MEDLINE Link].
Temtamy SA, McKusick VA. The genetics of hand malformations. Birth Defects Orig Artic Ser. 1978. 14(3):i-xviii, 1-619. [QxMD MEDLINE Link].
Malik S, Grzeschik KH. Synpolydactyly: clinical and molecular advances. Clin Genet. 2008 Feb. 73(2):113-20. [QxMD MEDLINE Link].
Tian F, Tian LJ, Zhao W, Li XC, Li B, Ji XL. Plastic repair for a case with synpolydactyly. Arch Orthop Trauma Surg. 2011 Jun. 131(6):869-73. [QxMD MEDLINE Link].
Castilla EE, Lugarinho R, da Graça Dutra M, Salgado LJ. Associated anomalies in individuals with polydactyly. Am J Med Genet. 1998 Dec 28. 80(5):459-65. [QxMD MEDLINE Link].
Jafari D, Sharifi B. A variant of mirror hand. A case report. J Bone Joint Surg Br. 2005 Jan. 87(1):108-10. [QxMD MEDLINE Link].
Bromley B, Shipp TD, Benacerraf B. Isolated polydactyly: prenatal diagnosis and perinatal outcome. Prenat Diagn. 2000 Nov. 20(11):905-8. [QxMD MEDLINE Link].
Zimmer EZ, Bronshtein M. Fetal polydactyly diagnosis during early pregnancy: clinical applications. Am J Obstet Gynecol. 2000 Sep. 183(3):755-8. [QxMD MEDLINE Link].
Ban M, Kitajima Y. The number and distribution of Merkel cells in rudimentary polydactyly. Dermatology. 2001. 202(1):31-4. [QxMD MEDLINE Link].
Eskandari MM, Oztuna V, Demirkan F. Late psychosocial effects of congenital hand anomaly. Hand Surg. 2004 Dec. 9(2):257-9. [QxMD MEDLINE Link].
Morley SE, Smith PJ. Polydactyly of the feet in children: suggestions for surgical management. Br J Plast Surg. 2001 Jan. 54(1):34-8. [QxMD MEDLINE Link].
Park GH, Jung ST, Chung JY, Park HW, Lee DH. Toe component excision in postaxial polydactyly of the foot. Foot Ankle Int. 2013 Apr. 34(4):563-7. [QxMD MEDLINE Link].
Dijkman R, Selles R, van Rosmalen J, Hülsemann W, Mann M, Habenicht R, et al. A clinically weighted approach to outcome assessment in radial polydactyly. J Hand Surg Eur Vol. 2015 Aug 28. [QxMD MEDLINE Link].
Hartzell TL, Taylor H. Traumatic amputation of a supernumerary digit: a 16-year-old boy's perspective of suture ligation. Pediatr Dermatol. 2009 Jan-Feb. 26 (1):100-2. [QxMD MEDLINE Link].
Katz K, Linder N. Postaxial type B polydactyly treated by excision in the neonatal nursery. J Pediatr Orthop. 2011 Jun. 31 (4):448-9. [QxMD MEDLINE Link].
Comer GC, Potter M, Ladd AL. Polydactyly of the Hand. J Am Acad Orthop Surg. 2018 Feb 1. 26 (3):75-82. [QxMD MEDLINE Link].

Media Gallery

Twenty-eight-day-old supernumerary digit, rudimentary nail unit cartilage (2x).
Twenty-eight-day-old supernumerary digit, nerve bundle base (40x).
Twenty-eight-day-old supernumerary digit, connective tissue and epidermis (40x).
Supernumerary digit, no magnification.

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Author

Luke Lennox, MD Physician

Disclosure: Nothing to disclose.

Coauthor(s)

Thomas N Helm, MD Professor of Dermatology, Hershey Medical Center, Penn State Health, Pennsylvania State University College of Medicine

Thomas N Helm, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Society for Dermatologic Surgery, American Society of Dermatopathology

Disclosure: Nothing to disclose.

Specialty Editor Board

Richard P Vinson, MD Assistant Clinical Professor, Department of Dermatology, Texas Tech University Health Sciences Center, Paul L Foster School of Medicine; Consulting Staff, Mountain View Dermatology, PA

Richard P Vinson, MD is a member of the following medical societies: American Academy of Dermatology, Texas Medical Association, Association of Military Dermatologists, Texas Dermatological Society

Disclosure: Nothing to disclose.

Robert A Schwartz, MD, MPH Professor and Head of Dermatology, Professor of Pathology, Professor of Pediatrics, Professor of Medicine, Rutgers New Jersey Medical School

Robert A Schwartz, MD, MPH is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, New York Academy of Medicine, Royal College of Physicians of Edinburgh, Sigma Xi, The Scientific Research Honor Society

Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD Professor and Chairman, Department of Dermatology and Dermatologic Surgery, Medical University of South Carolina College of Medicine

Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Additional Contributors

Albert C Yan, MD Section Chief, Associate Professor, Department of Pediatrics, Section of Dermatology, Children's Hospital of Philadelphia and University of Pennsylvania School of Medicine

Albert C Yan, MD is a member of the following medical societies: American Academy of Dermatology, Society for Investigative Dermatology, Society for Pediatric Dermatology, American Academy of Pediatrics

Disclosure: Nothing to disclose.

Carter G Abel, MD Clinical Assistant Attending, Department of Dermatology, New York Presbyterian Hospital

Carter G Abel, MD is a member of the following medical societies: American Academy of Dermatology, American College of Mohs Surgery, American Society for Dermatologic Surgery, Medical Society of New Jersey

Disclosure: Nothing to disclose.

Denise M McCarthy, MD Associate Professor, Department of Radiology, Morristown Memorial Hospital

Denise M McCarthy, MD is a member of the following medical societies: American Association for Women Radiologists, American Roentgen Ray Society, Association of University Radiologists, Radiological Society of North America

Disclosure: Nothing to disclose.

Supernumerary Digit Clinical Presentation

History

Physical Examination

References

Tables

Contributor Information and Disclosures

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